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The Benthic Exchange of O2, N2 and Dissolved Nutrients Using Small Core Incubations
Published on: August 3, 2016
Nitrous oxide emission in a laboratory anoxic-oxic process at different influent pHs: Generation pathways and the
Jingbo Guo1, Qiwei Cong2, Jun Zhang3
1School of Civil and Architecture Engineering, Northeast Electric Power University, Jilin 132012, China.
Abstract:
This study focused on the nitrous oxide (N2O) generation from the biological nitrogen removal process under different pH levels. To explore a pH optimum, the online N2O emission and the bacterial composition and function in the anoxic-oxic process were investigated. The mean gaseous N2O emission accounted for 0.329%, 0.103%, 0.085%, and 0.793% of the influent total nitrogen at pH of 5, 6, 8, and 9, respectively. Incomplete oxidation in oxic tanks was the primary source of N2O, while N2O in the anoxic tank was mainly generated by nitrifier denitrification. No direct correlations were observed between N2O emission and potential nitrifiers and denitrifiers. The impacts of pH on N2O generation were more likely related to the response of bacterial enzymes and nitrogen compounds, rather than the feedback of bacterial community structure itself. Above all, an influent pH range of 6-8 is recommended for nitrogen removal and N2O mitigation in anoxic-oxic process.
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